I believe on almost every ASIC you will find a sensitve PLL. This means that we have to terminate every databusses that comes from a memory, if it exceeds the DC max level .

Joachim

Matt (boomer) Russell wrote:

> hi,>> The problem, at least for ASIC vendors, is that I don't know all the> circuits that you are going to have on the chip and so we have to assume> that something in the chip won't like high frequency noise coupled onto> the power rails.>> Even if the IO rails are issolated from the core supplies (something> that is not really possible for a common ground substrate) That noise> could also get coupled through the package.>> That is why alot of times all that you see is the DC max level which> is essentialy the limit for not turning on the clamp diodes.>> This is a limit that I have been struggling with so any comments on> how to look at this would be appreciated.>> matt>> Scott McMorrow wrote:> >> > Jim,> >> > Jim_Pankratz@Dell.com wrote:> >> > >> > > Why do we not see Maximum AC Operating Conditions in current data sheets?> > >> > >> >> > This is a good question. It would be nice to have some sort of> > maximum energy over a particular voltage, since the problem is> > a time/voltage(current) phenonemon.> >> > It would also be nice to have a decent way of specifying the> > sensitivity of an input to high frequency energy such as noise> > and glitches in the threshold region. The Pentium Pro/PII/PIII> > specs from Intel take a stab at this. The spec, however, is> > a bit kludgey.> >> > regards,> >> > scott> >> > **** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****>> **** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****

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